from Ojou-sama Yomeiri Kousou!
Origin
Japan
Ageha is the daughter of the Black Rose mafia leader who rules the southern half of the city. She has silver hair with twin tails and fair skin. She is in love with Mamoru and has accepted to be his little sitter in order to be with him. She and Sakura (her enemy) both love Mamuro and they compete to be the one who Mamoru will love.

Ojou-sama Yomeiri Kousou!
Based on a light novel by Tsukino Otogi with illustrations by Yuyi. One day, Amakawa Mamoru receives two love-letters. When he goes to meet their senders at the appointed place, the rooftop, he finds two diametrically opposite girls waiting for him. One, Sumiyoi Sakura, is a refined black-haired beauty and quintessential Yamato Nadeshiko. The other, Kurosaki Ageha, is a doll-like twin-tailed platinum blonde. However, when they realise that they had both sent love letters to the same person, hostilities broke out with one drawing a katana, and the other a pair of pistols. It turns out that Sakura belongs to a yakuza family, while Ageha is from a mafia family, and the town is evenly split into two between them.